1. Field of the Invention
Smart tags are presently used for a number of applications in both the civilian and military sectors. These applications include item identification, toll passes, and barrier tagging. These tags are relatively expensive, costing several dollars, and are limited in the amount of information they can store. These tags cannot be used in large quantities, because of the cost involved, especially in circumstances where they can not be recovered for reapplication.
Both military and civilian sectors require low cost tags costing few cents each for many different applications especially for use in large quantities where tag recovery is impractical. Some applications for Government use include tagging individual weapons, munitions or pieces of equipment, crates, and other inventory. Some civilian applications include tagging baggage in airports, parcels, packages, crates, individual items, files, folders, and dockets, inventory, shop merchandise, and for employee and vehicle identification.
Tagging baggage at airports is an important application. It will be beneficial to have a smart baggage tagging system which can store detailed information. This will allow to track the history of baggage: point of origin, travel route, and a profile of the owner. Such information will require significant amount of non-volatile memory.
The size of the tag is also important so that it can be placed onto baggage and cargo inconspicuously. Therefore, the size of the tag should be smaller than about 5×5×0.3 mm3.
The tag should not require any external power or antenna. Even a tiny battery or a small antenna will increase the size and complexity due to the connection of the battery and/or the antenna to the chip; at the same time tag's cost increases dramatically. A battery has a finite lifetime and the probability of failure during application is greater. A tag with the required power generated on board by the remote programmer/reader would be a better solution for accommodating power needs.
Development of such a smart tag requires a suitable applicator. The applicator must be simple in design and cost-effective. The applicator must be able to apply the smart tag onto any type of package, bag, box, luggage, and crate of various thickness and stiffness while they are transported on a conveyor. The applicator must apply the tag onto the baggage item as it is moving with arbitrary order, shape, size, orientation, and position. It must work fast, as the conveyor can reach a maximum speed of one meter per second with about one meter spacing between each item. The tag must adhere easily to different kinds of luggage material such as, cloth, metal, plastic, paper, leather or wood.
2. Description of Related Art
FIG. 1 shows the reproduction of an article in EDN magazine (Jun. 19, 1997) that presents recent progress in the area of radio-frequency identification RFID) tag chips. The size of the tags shown is 61×10×0.1 mm3 (610 mm2 area), which obviously makes them too large for the kind of automatic application of this disclosed invention. In the case of SCS Corp.'s tag chip shown in FIG. 1, the size of the RF antenna needed for the communication between tag chip and remote programmer/reader places a limit on the reduction in size that can be achieved. By using higher frequencies and carefully investigating of the antenna design, this limitation of the prior art. The size of the applicant's MicroTAG chip is 16 mm2 (future versions are expected to be 9 mm2) which is nearly 40 times (or ≧68 times) smaller than the SCS Corp. tag chip. The SCS chip also requires mounting the antenna onto the chip where applicant's MicroTAG chip has both the transmission and receiving antennas on chip and does not require any mounting.